A conventional method for plating of polymeric material is, in general, a method wherein a tin-palladium compound is absorbed by the surface of a mold made of polymeric material after the surface has been roughened by chemicals, palladium is reduced and, finally, electroless plating is carried out. In addition, an exposure method using a photoresist is used in order to partially plate a circuit pattern, or the like.
In addition, these two steps are repeated and, thereby, multi-layered substrates, which are widely used for electronic apparatuses, are manufactured.
That is to say, pre-drying is carried out in the via formation step after the application of an insulating layer 61 to a substrate 60, as shown in FIGS. 5(1) to 5(6), exposure (negative) treatment 64 is carried out for development and, after that, main drying is carried out. Next, insulating layer 61 is etched (roughened) in the pretreatment step, as shown in FIGS. 5(7) to 5(9) and undergoes a catalyzing step and an acceleration step. Next, electroless plating or electrolytic plating subsequent to electroless plating is carried out on the pretreated insulating layer 61 in the patterning step, as shown in FIGS. 5(10) to 5(15), and a resist 62 is applied, an exposure (positive) treatment 65 is carried out for development and, after that, Cu is etched and resist 62 is removed so as to gain a circuit pattern 63 made of a plated layer.
In addition, though the partial plating method for an injected mold circuit part (MID) is same as described above, multiple layers of plating on an injected mold circuit part by means of an exposure method is not implemented because an appropriate resist material or an application method does not exist for a three-dimensional part and a three-dimensional exposure is technically and productively difficult.
In addition, though a combination of double plating and an exposure method carried out on the surface of the outermost layer has been proposed as another means for formation of multiple layers on an injected mold circuit part, only three layers can be formed and circuit formation is extremely limited using this means.
Many manufacturing steps are required, however, for the manufacture of a multi-layered substrate using the above described conventional method for plating a polymeric material and an exposure method utilizing a photoresist and a multi-layered substrate cannot easily be manufactured and, moreover, a maximum of only three layers can be formed according to multi-layered formation on an injected mold circuit part such that there is a problem wherein circuit formation is extremely limited and the cost of manufacture becomes high.
The present invention is provided to solve the above described problems and the first purpose thereof is to provide a circuit formation part wherein polymeric material filled with inorganic filler is diluted with a solvent and is applied to a base for resin application and, then, is dried so as to form an insulating layer and, thereby, plating by means of surface treatment with a laser becomes possible in a manner such that a circuit for a multi-layered substrate is formed from this plating.
In addition, the second purpose of the present invention is to provide a circuit formation part that has an arbitrary circuit form and wherein a multi-layered circuit, even of three or more layers, can be gained and that can easily be reduced in size and in weight, that can easily be increased in density and that has excellent EMC characteristics.
In addition, the third purpose of the present invention is to provide a manufacturing method for a circuit formation part, wherein a circuit formation part having an arbitrary circuit form and having a multi-layered circuit in three-dimensions, even of three or more layers, can easily be manufactured at a low cost.